Abstract: A heat exchanger 15 is disposed in an oil passage 14 provided in a hydraulic pressure circuit 9 of a hydraulically operated transmission, to conduct heat exchange between cooling water for an engine 2 and hydraulic fluid.

Abstract: A control apparatus for a hydraulically-operated vehicular transmission, to buffer in-gear shocks in any driving condition of a vehicle, includes a pressure regulating solenoid valve for controlling an oil pressure in a hydraulic engaging element which establishes a predetermined speed transmission train of the hydraulically-operated vehicular transmission, an accumulator connected to an oil passage which is communicated with the hydraulic engaging element, a discriminator for discriminating whether the pressure accumulation in the accumulator-has been completed or not, and a controller for maintaining an outlet pressure of the pressure regulating solenoid valve at a predetermined pressure until the pressure accumulation in the accumulator has been completed and for increasing the output pressure of the pressure regulating solenoid valve, after the pressure accumulation in the accumulator has been completed, depending on a driving condition of the vehicle.

Abstract: Shift valves 141, 142, 143 are provided to switch oil passage connections to a state in which an oil pressure in one hydraulic clutch of an arbitrary speed transmission train and an oil pressure in a hydraulic clutch of a transmission train which is adjacent thereto as seen in the order of speed are controllable by a pair of linear solenoid valves 201, 202. Skipped speed change from a predetermined first speed transmission train to a second speed transmission train which is not adjacent to the first speed transmission train is made possible. In concrete, a large-capacity accumulator A5 is connected to an oil passage L19 which is in communication with 5th-speed hydraulic clutch C5. At the time of skipped speed changing from 5th speed to 3rd speed, shift valves 141, 142, 143 are switched to a state of 3rd-4th speed change. The oil pressures in the hydraulic clutches C3, C4 for 3rd and 4th speed transmission trains, respectively, are made controllable by the linear solenoid valves 201, 202.

Abstract: An automatic transmission includes a first speed clutch and a first speed hold clutch side by side, and a first speed hold gear shift stage is smoothly established and the responsiveness of disengagement of the first speed clutch is enhanced, particularly at low temperatures. The first speed clutch and the first speed hold clutch are provided side by side, a second clutch piston for engaging the first speed hold clutch, is installed in a relatively movable manner inside a first clutch piston for engaging the first speed clutch, and a check valve is provided on the first clutch piston. When a first speed hold gear shift stage is established, after first speed clutch has been engaged by supplying hydraulic fluid to a fire clutch oil chamber, the first speed hold clutch is engaged by supplying hydraulic fluid to a second clutch oil chamber.

Abstract: An increase in an oil pressure PCL in a hydraulic engaging element at the time of gearing in is appropriately controlled to buffer in-gear shocks in any driving conditions of a motor vehicle. A pressure-regulating solenoid valve to control an oil pressure PCL of the hydraulic engaging element is provided, and an accumulator is connected to an oil passage communicated with the hydraulic engaging element. As a parameter to show the degree of slipping of the hydraulic engaging element, an input/output speed ratio r (output side rotational speed/input side rotational speed) of the hydraulic engaging element is searched.

Abstract: At downshifting, hydraulic pressure of hydraulic clutch on engaging side (ON clutch pressure) is increased when an input and output speed ratio ("Gratio") has fallen below a predetermined value YGDNS. YGDNS is variably set depending on the vehicle speed and the engine temperature so that it becomes a lower value at a high vehicle speed than at a low vehicle speed, and a higher value at a low engine temperature than at a high temperature. When a downshifting command to a still lower speed stage is issued during downshifting control (when FTBD=1), a downshifting completion processing is performed in the course of the downshifting control (step in S111). Oil pressure in a hydraulic engaging element on the disengaging side QDNOFF and oil pressure in a hydraulic engaging element on the engaging side QDNON are switched to the oil pressures at the time of completion of downshifting, to thereby complete the first step downshifting control at an early time.

Abstract: A control system of a lockup clutch of a torque converter of a vehicle automatic transmission. A basic manipulated variable is determined in response to the vehicle operating condition in accordance with a predetermined characteristic, and the lockup clutch engaging force is controlled in response to the variable. In the system, fuzzy reasoning is carried out using the detected vehicle operating parameters to correct the basic manipulated variable, and the engaging force is controlled in response to the corrected manipulated variable, when the control condition is met. The corrected manipulated variable is gradually decreased with respect to time when the vehicle driving state has shifted from a region in which the engaging force is controlled in response to the corrected manipulated variable to a region in which the lockup clutch is disengaged.

Abstract: Upshifting is performed in a short time without giving rise to shocks. For that purpose, at the time of upshifting, a hydraulic pressure (QUPOFF) of a hydraulic engaging element on disengaging side is controlled such that the input and output speed ratio ("Gratio") of a transmission is decreased to, and held at, a predetermined slipping region (YG(N)S) that is lower than an engaging region (YG(N)L)-YG(N)H) to be set based on a gear ratio which is established by the engagement of the hydraulic engaging element on the disengaging side. The hydraulic pressure (QUPON) of a hydraulic engaging element on engaging side is gradually increased. When "Gratio" once falls below YG(N)L and then increases up again to YGCONOK, QUPOFF is lowered to a predetermined low pressure (QUPOFFB) at a lapse of a predetermined time (YTMUP8). Once "Gratio">YGCONOK, QUPON is increased to a predetermined high pressure QUPONB at a lapse of a second predetermined time YTMUP3.

Abstract: The disadvantage in the conventional transmission in which a high speed stage is established during the initialization operation by the starting up of an electronic control circuit, is eliminated. The disadvantage is that the rotational speed of an engine lowers due to the establishment of the high speed stage during the initialization operation at the time of running in a low speed stage, with the result that the recovery of the driving force after the completion of the initialization operation is delayed. To solve this disadvantage, valves that can switch the transmission to a neutral condition in the running range are provided. During the initialization operation of the electronic control circuit (20), a neutral signal which shifts the transmission (1) to the neutral condition is output (S902) to the valves.

Abstract: There are prevented shocks that will occur when a switchover speed changing is made to transfer from one speed changing, in the midst of that speed changing, to another speed changing when the input and output speed ratio "Gratio", which serves a control parameter, is not accurately detected. For that purpose, there is used a flag FGFAIL for setting "1" when the input and output speed ratio "Gratio", at the time of non-speed changing, does not lie within a predetermined range based on the gear ratio of the speed stage that is being established at that time. A switchover speed changing in which switching to another speed changing is made during a speed changing is prohibited when FGFAIL=1.

Abstract: A control system of a lockup clutch of a torque converter of a vehicle automatic transmission. A basic manipulated variable is determined in response to the vehicle operating condition in accordance with a predetermined characteristic, and the lockup clutch engaging force is controlled in response to the variable. In the system, fuzzy reasoning is carried out using the detected vehicle operating parameters to correct the basic manipulated variable, and the engaging force is controlled in response to the corrected manipulated variable, when the control condition is met. The corrected manipulated variable is gradually decreased with respect to time when the vehicle driving state has shifted from a region in which the engaging force is controlled in response to the corrected manipulated variable to a region in which the lockup clutch is disengaged.

Abstract: A system for controlling a vehicle automatic transmission, in which a gear ratio to be shifted to is determined based on the vehicle speed and throttle opening degree and a clutch is supplied with hydraulic pressure such that the rotational speed of the transmission input shaft concurs with a desired rotational speed change rate. The system includes means for discriminating whether the engine load fluctuates and the operation is discontinued when it is discriminated that the engine load fluctuates. Specifically, even when the accelerator pedal is operated only somewhat rapidly and the engine output is able to follow the change in the degree of throttle opening, the degree of throttle opening nevertheless differs between that at the start of gearshift and that in the course of gearshift thereafter, causing unexpected gearshift shock to occur. The arrangement can solve the problem.

Abstract: A gearshift controlling system for controlling a vehicle automatic transmission. In the system, a first alternative throttle opening degree is predetermined in case of failure of a throttle position sensor, and a second alternative throttle opening is similarly determined such that a gear ratio can be determined based on the detected vehicle speed and the second alternative engine load in a gear ratio decreasing or increasing direction. Either of the first alternative throttle opening degree or the second alternative throttle opening is selected and the gear ratio to be shifted to is determined in accordance with the predetermined gearshift schedule based on the detected vehicle speed and the selected alternative engine load, to output the gearshift command, thereby preventing unexpected gearshift to occur.

Abstract: In an apparatus for controlling an automatic transmission for a vehicle in which, at the time of gear engagement due to changing over from a reverse range or a neutral range to a forward range, a speed-change stage of the automatic transmission is shifted down to a low-speed stage after once setting it to a predetermined high-speed stage. The apparatus has a detector for detecting an amount of slippage of high-speed stage engaging elements which establish the high-speed stage and a control device for controlling to shift down, at the time of gear engagement, to the low-speed stage after the amount of slippage of the high-speed stage engaging elements has lowered to a predetermined value or smaller.